Protest outside Greek parliament – Thousands shout slogans in front of the Greek parliament during a general strike in Athens on Wednesday. The first nationwide strike since Greece's new coalition government was formed in June was called by Greece's two biggest labor unions.

The Greek government is seeking new ways to implement budget cuts of 11.5 billion euros ($14.49 billion) to ensure the country receives another international bailout installment in October.

The one-day strike in protest against further cuts was organized by the two biggest unions in the country, with rallies in a number of cities across Greece, including Patras, west of Athens.

CNN iReporter Costas Liveris, a public worker, was among those taking part in the demonstration in the capital.

Liveris, 36, has been hit hard by the country's economic crisis, losing 50% of his salary and barely clinging to his job as the price of basic foodstuffs continues to rise.

"I'm furious because even after the elections, we got promises but nothing [from the government]," he said. "It's the same policy but just a different party.

"For the last few hours on the protest, me and my colleagues discussed how disappointed we are. We have no hope."

Liveris said he and his fellow Greeks stand in total support of the Spanish people who protested against austerity Tuesday evening. "It is the same policies that strangle the same people. We 100% stand with the Spanish," he said.

Dozens of people were injured and arrested as protesters and police clashed in central Madrid. Demonstrators said police were shooting into the crowd with rubber bullets, although police would not comment. Officers at one point baton-charged the protesters to prevent them from approaching the Spanish parliament, which was in session.

As large numbers began to assemble in Athens and other cities earlier Wednesday, Constantine Michalos, president of the Athens Chamber of Commerce, said he hoped the strike would not turn violent.

Many people are tired of years of government-imposed belt-tightening measures that have not worked, Michalos said.

"The Greek people have taken up tremendous sacrifices in this time period, and it just has not delivered the desired results," Michalos said.

"Where we need to concentrate today is not on further austerity measures, because there have been extreme sacrifices made by Greek people in the last three years. What we need is to advance growth and stimulate the economy."